1. Field of Invention
The present invention relates to a method of manufacturing an electrooptical device and an apparatus to manufacture the same, an electrooptical device and electronic appliances including the electrooptical device. In particular, the present invention relates to a method of manufacturing an electrooptical device including a luminous element, such as an organic EL element, an electrooptical device, and electronic appliances.
2. Description of Related Art
Related art electrooptical devices such as liquid crystal device and organic EL (electroluminescence) device include a plurality of circuit elements, electrodes, and a liquid crystal or an EL element laminated on a substrate. For example, the organic EL device has a luminous element including a luminous layer containing luminous substances interposed between electrode layers of an anode and a cathode. Positive holes injected from the anode side and electrons injected from the cathode side are recombined in a luminous layer having light emitting ability, and light is emitted when the electrons are deactivated from an excited state.
However, the related art electrooptical device as described above is subject to the following problems.
Since the organic EL device having the above construction includes an electric current driving luminous element, an electric current is required to flow between the anode and cathode to emit light. Consequently, the element is heated while emitting the light, and the element is deteriorated by accelerating oxidation of the materials constituting the element due to oxygen and moisture, when the element is placed in an environment containing oxygen and moisture. Alkali metals and alkali earth metals used for the cathode are particularly liable to be oxidized. Generation and growth of dark spots are representative examples of deterioration of the element by oxidation and moisture. The dark spots mean defects of luminous points. Decrease and instability of luminance due to decrease of stability with time, and short service life have been the problems related to advanced deterioration of the luminous element related to driving of the organic EL device.
Accordingly, a method of blocking the electrooptical device from the atmosphere has been developed as one of the countermeasures to reduce or suppress the element from being deteriorated, wherein a substrate on which the luminous element is disposed and a seal member are integrated with an adhesive, and the luminous element is disposed in a space formed with the substrate, seal member and adhesive. However, since the substrate and seal member may slip out of position unless the electrooptical device is transferred after the adhesive has been completely hardened when, for example, the electrooptical device is transferred during the manufacturing process, it creates a problem that productivity is decreased because the electrooptical device cannot be transferred, or the transfer speed should be slow even when it is transferred, before the adhesive is completely hardened.
The invention addresses or solves the above and/or other problems, and provides a method of manufacturing an electrooptical device by which high productivity is maintained in bonding a substrate and seal member, an electrooptical device, and electronic appliances including the electrooptical device.
The present invention provides a method of manufacturing the electrooptical device including a first member on which an electrooptical element is disposed, and a second member covering the electrooptical element, including:
(a) feeding an adhesive material to first and second regions of a joint region to bond the first member and second member;
(b) bonding the first member and second member with the adhesive material;
(c) hardening the adhesive material fed to the first region of the joint region; and
(d) hardening the adhesive fed to the second region of the joint region after the step (c).
Preferably, step (a) in the above manufacturing method includes:
(a-1) feeding a first adhesive material to the first region of the joint region; and
(a-2) feeding a second adhesive material different from the first adhesive material to the second region of the joint region.
According to the present invention, the first member and second member may be temporarily assembled with the first adhesive material within a short period of time to reduce an waiting time of hardening, by disposing first material and second material at the bonding region, and by employing, for example, a material capable of hardening within a short period of time by a first treatment as the first adhesive material. Accordingly, efficiency of succeeding manufacturing steps may be enhanced while maintaining high productivity. An electrooptical device exhibiting desired performance, may be manufactured using the second adhesive, by employing a material having desired performance such as high sealing ability, as the second seal material. The luminous element is formed between the first member and second member using a material having high sealing performance as the second adhesive in order to hermetically seal the luminous element with the first member and second member.
The first adhesive is a light-curable adhesive, and the second adhesive is a thermosetting adhesive. Desirably, step (c) includes:
(c-1) irradiating a light having a prescribed wavelength to a light-curable material fed on the first region; and
step (d) includes:
(d-1) heating a thermosetting material fed on the second region.
Consequently, the first and second members can be temporarily assembled within a short period of time by irradiating the first material with a light, such as a UV light. Employing the thermosetting material as the second material enables sealing performance to be enhanced. The first adhesive material and second adhesive material may be any adhesives capable of bonding the first member and second member, and the adhesive available includes the adhesives including the UV curable material and thermosetting material as described above, as well as an EB (electron beam) curable material, two-part curable materials and thermoplastic materials called as hot-melt materials. The material suitable for the first adhesive is able to temporarily assemble the first member and second member by hardening within a short period of time, and the material suitable for the second adhesive material is able to reduce or block air and moisture from invading into the space formed between the first member and second member.
Desirably, steps (a) to (d) are performed in an inert gas atmosphere in the manufacturing method above in order to prevent the luminous element from being deteriorated or reduce such deterioration. The inert gas as used herein is a gas that is inert to the luminous element including nitrogen gas and argon gas.
In the manufacturing method above, step (a) desirably includes:
(a-3) discontinuously feeding the adhesive material to the first and second regions of the joint region.
Step (b) desirably includes:
(b-1) compressing the first member and second member so that the adhesive material fed discontinuously in the step (a-3) contacts with each other.
The adhesives may be overflowed to the portions outside of the joint region to cause poor hermetic sealing when the first member and second member are compressed in step (b). However, since the first adhesive material or second adhesive material is discontinuously disposed, the pressurized gas within the space formed between the first member and second member can be discharged through discontinuous parts (gaps) at the initial stage of compression. Since the first member and second member are quite intimately contact with each other thereafter, the adhesive materials form a continuous layer due to a capillary action generated, and the space formed between the first and second members are completely isolated from the external environment and hermetically sealed.
Using other materials, such as a hygroscopic material, together with the first and second adhesive materials permits moisture to be reduced or prevented from invading into the luminous element from the outside to enable the element to be further protected from being deteriorated. High performance of the electrooptical device may be also expected by using a material having desired functions as the other material. The other material as used herein may be an adhesive capable of bonding the first member and second member, or may be a material other than the adhesive.
The second region of the joint region is wider than the second region in the manufacturing method above. Desirably, step (a) includes:
(a-4) feeding the light-curable material to the first and second regions of the joint region;
step (c) includes:
(c-1) irradiating a light having a prescribed wavelength to the light-curable material fed on the first region; and
step (d) includes:
(d-2) irradiating a light having a prescribed wavelength to the light-curable material fed at least on the second region.
According to the present invention, the first and second members can be temporarily assembled within a short period of time by curing the light-curable material in the first region by irradiating a light to the first region in the first light-irradiating step (c-1) after feeding the light-curable material to the joint region. Consequently, efficiency of the subsequent manufacturing steps may be enhanced by shortening the waiting time of hardening. Irradiating a light to the second region as a region wider than the first region (step (d-2) permits the bonding force between the first member and second member to be enhanced by hardening the light-curable material in the second region. Workability and productivity may be enhanced by independently applying the first light-irradiation step by which the first member and second member are temporarily assembled by hardening a part of the light-curable material, and the second light-irradiation step by which all the light-curable material is hardened. Hardening all the light-curable material at the second light-irradiation step allows a highly hermetic sealing to be attained, thereby enabling an electrooptical device that can exhibit desired performance to be manufactured by preventing the luminous element from being deteriorated. When the first region and second region are isolated with each other, the first region irradiated with a light in the first light-irradiation step accounts for less than 50% of the entire light-curable material disposed at the joint region. When the first region is considered to be a part of the second region, on the other hand, the first region irradiated with a light in the first light-irradiation step may account for less than 100% of the entire light-curable material (or second region) disposed at the joint region.
The first and second regions of the joint region are preferably defined based on the light irradiation range in steps (c) and (d).
The above steps desirably include:
(e) exposing the first and second members after bonding to an atmosphere of a prescribed temperature for a prescribed period of time after step (d).
The light-curable material is completely hardened by allowing to stand still in an atmosphere of a prescribed temperature for a prescribed period of time, and the bonding force between the first member and second member is further reinforced. The UV-curable material is preferably used as the light-curable material, and the light irradiated to the first region and second region is preferably a UV light.
The present invention provides an apparatus of manufacturing an electrooptical device including a first member on which an electrooptical element is disposed, and a second member covering the electrooptical element. The manufacturing apparatus includes an adhesive material feed unit to feed an adhesive material to the first region and second region of a joint region to bond the first member and second member; a bonding unit to bond the first member and second member by use of the adhesive material; a first adhesive material hardening unit to harden the adhesive material fed on the first region of the joint region; and a second adhesive material hardening unit to harden the adhesive material fed on the second region of the joint region after hardening the adhesive material by the first adhesive material hardening unit.
It is desirable that the adhesive material feed unit includes a first feed unit to feed a first adhesive material to the first region of the joint region, and a second feed unit to feed a second adhesive material different from the first adhesive material to the second region of the joint region.
The first member and second member may be temporarily assembled with the first adhesive material in the present invention by feeding the first adhesive material capable of hardening within a short period of time to the joint region with the first feed unit, enabling the subsequent manufacturing steps to be efficiently performed. Hermetic sealing performance to the luminous element may be enhanced by feeding the second adhesive material having high hermetic sealing performance using the second feed unit, and the element is protected from being deteriorated. Consequently, the electrooptical device manufactured can exhibit its desired performance. It is also possible to simultaneously feed the first adhesive material and second adhesive material by taking advantage of the construction including two feed units in order to enhance productivity. Naturally, the feed unit is not necessarily required to include two units, and arbitrary number of plural, or three or more units, may be provided. The construction may comprise the first feed unit to feed the first adhesive material on the members and the second feed unit to feed the second adhesive material on the members, or include the first feed unit and second feed unit to feed the same adhesive on the members.
It is desirable that each of the first feed unit and second feed unit is independently movable relative to the joint region. Consequently, the first adhesive material and the second adhesive material be simultaneously fed without interference between the first feed unit and second feed unit, thereby enabling workability to be enhanced.
The manufacturing apparatus desirably includes a sensing unit to detect the distance between the joint region and each of the first and second feed apparatus, and an adjustment unit to adjust the positions of the first and second feed units based on the result of detection of the sensing unit. This construction of the apparatus enables each of the first feed unit and second feed unit to feed the adhesive materials from their enhanced or optimum positions to the joint region, and a desired adhesive material may be fed to a desired position of the joint region.
It is desirable in the manufacturing apparatus that the adhesive material feed unit is able to feed the adhesive material with a predetermined pattern, since a desired quantity of the adhesive material may be fed to the desired position of the joint region, thereby permitting bonding performance to be enhanced with efficient bonding by reducing or suppressing excessive use of the adhesive.
Desirably, the second region of the joint region is wider than the first region in the manufacturing apparatus described above, the adhesive material fed by the adhesive material feed unit is the light-curable material, and the first and second adhesive material hardening units include first and second irradiation units to irradiate a light having a wavelength capable of hardening each light-curable material.
According to the present invention, the light-curable material is disposed on the joint region by the adhesive material feed unit, and the light-curable material in the first region as a part of the light-curable material can be hardened within a short period of time by irradiating a light from the first irradiation unit. Consequently, the first member and second member may be temporarily assembled within a short period of time, and the waiting time of hardening may be shortened, thereby performing the subsequent manufacturing steps with good efficiency. The bonding force between the first member and second member may be reinforced by irradiating the light to the second region wider than the first region by the second irradiation unit to harden the light-curable material in the second region. Workability and productivity may be enhanced by independently providing the first light-irradiation unit to temporarily assemble the first member and second member by hardening a part of the light-curable material, and the second light-irradiation unit to harden the entire light-curable. A highly hermetic sealing ability may be attained by hardening the entire light-curable material using the second light-irradiation unit, so that an electrooptical device exhibiting desired performance may be manufactured by protecting the luminous element from being deteriorated.
The first light-irradiation unit includes a light source to emit a light, a shunting unit to shunt the light emitted from the light source, and an irradiation unit to irradiate the light shunted by the shunting unit to prescribed plural positions on the joint region. The first region of the joint region is desirably determined based on the prescribed position where the irradiation unit is able to irradiate the light.
Consequently, the light can be simultaneously irradiated to prescribed plural positions of the light-curable material fed to the joint region. Accordingly, temporary assembling of plural sites of the first and second members may be promptly effected using a simple construction of the apparatus, thereby enabling temporary assembling to be stabilized.
It is desirable that a holding unit capable of holding at least one of the first and second members is provided, and the irradiation unit is held with the holding unit. Consequently, the adhesive material may be hardened by irradiating a light while compressing, for example, the second member onto the first member with the holding unit.
The electrooptical device according to the present invention includes an electrooptical element, a first member to mount the electrooptical element, a second member to cover the electrooptical device, a first adhesive material fed to a first region in the joint region to bond the first member and second member to temporarily assemble the first member and second member, and a second adhesive material fed to the second region to bond in order to finally secure the first member and second member.
Desirably, the first adhesive material is a light-curable material, and the second adhesive material is a thermosetting material.
The electronic appliances according to the present invention include the electrooptical device according to the present invention.